1. Field of the Invention
This invention relates generally to medical equipment for Magnetic Resonance Therapy (MRT), and more specifically to electromagnetic therapy for reduction of symptoms and for curing a large variety of physical and mental conditions.
2. Description of Related Art
There is abundant history of magnets being used for medical treatment. In 440 BC, Socrates utilized magnetite in the treatment of menstrual disorders. Magnetite is a member of the spinel group of minerals which has the standard formula A(B)2O4. The A and B usually represent different metal ions that occupy specific sites in the crystal structure. In the case of magnetite, Fe3O4, the A metal is Fe +2 and the B metal is Fe +3; two different metal ions in two specific sites. This arrangement causes a transfer of electrons between the different irons in a structured path or vector. This electric vector generates the magnetic field. Common present day systems utilize electric currents through conductive coils to flexibly generate variable magnetic fields spatially and temporally.
In 1857 Dr. Al Pulvermacher of Vienna introduced an “Electromagnetic Belt” in England. More recently, Fallus, in U.S. Pat. No. 4,197,851, issued on Apr. 15, 1980, utilizes magnetic fields applied to a patient through the application of an electrode to the body for electrotherapeutic treatment. In Fallus' U.S. Pat. No. 4,454,883, issued on Jun. 19, 1984, weak electromagnetic fringe fields are employed for the control of tremors and seizures, and disorders of the autonomic nervous system such as panic attack.
Loos, in U.S. Pat. No. 6,167,304, issued on Dec. 26, 2000, teaches an apparatus for manipulating the nervous system using an external electric field with variable pulse parameters, and Long, et al. in U.S. Pat. No. 6,029,084, issued on Feb. 22, 2000, utilizes electromagnetic fields in synchronization with the heart, and in an earlier UK Patent GB-2156679-B, issued on Sep. 16, 1987, offers relief for migraine, hypertension, lower back pain, and premenstrual tension. No prior art has been found for electromagnetic therapy using digitally generated unipolar magnetic fields, nor with temperature control of the electrodes.
Magnetic Resonance Therapy (MRT) involves the use of electromagnetic fields applied to the body for beneficial effects. The buildup of calcium phosphate and calcium carbonate in the cells of the body contribute to degradations in teeth, joints, heart, etc. Since calcium molecules are paramagnetic they align and become cemented together as stones, granulomas, and plaque. The application of periodic oscillatory magnetic fields to regions of the body loosens the calcium molecular bonds allowing these deposits to free and exfoliate into the blood stream for removal by the kidneys.
Magnetic therapy has become a standard medical treatment for many conditions or diseases in Eastern Europe, Asia and former USSR countries. Magnetic therapy is an innovative, emerging medical technology, with an extensive biological research base. For example: the use of MRT in the healing of non-union fractures, and in nerve conduction testing.
The roots of this bioscience come from the studies done in biomagnetics, the study of the body's own magnetic fields. All human activity is conditioned by the earth's magnetic environment, and in the last two decades biomedical knowledge has advanced dramatically in the area of bioelectricity, not only in nerve conduction but also in electrolytic phenomena.
Magnetic forces exist in the space around moving electrical particles, which can affect other moving particles. The source of these forces can be electrons in wires where electric current flows, ions in electrolytic solutions, electrons in cathode ray tubes, etc. The static magnetic field around permanent magnets is based on the same principle. In the permanent magnet, motion of electrons (spin and orbital motion moment) is arranged such that “magnetic field” forces exist outside of the magnet as magnetic flux.
Magnetic fields can be classified according to their space attributes as uniform or non-uniform. Uniform fields are those where in every point of the field area of interest substantially the same value (strength and sign) and direction is exhibited, such as the condition of a static passive magnet or electromagnet with direct current (DC) flowing therein. In current magnetic therapy applications non-uniform fields are generally used.
In time varying magnetic fields, magnetic flux density or intensity changes with time, typically periodic at specific frequencies. Time varying magnetic fields result from electromagnets fed with non-constant currents, e.g. alternating (AC) currents. The most common varying fields are found around electrical wires conducting AC current, such as to electrical appliances.
Magnetic fields are characterized by intensity (H) and magnetic flux density (B). The intensity of a magnetic field is directly proportional to the current flowing through a wire and indirectly proportional to the distance from the wire:H=I/2nrWhere I=current intensity in amperes, r=distance from the wire in meters. The unit of H is ampere/meter (A/m) defined as the intensity of a magnetic field at a distance r=½ n from the wire wherein a current of 1 A is flowing.
Magnetic flux density is measured in units of Tesla (T). This unit is defined as follows: if a force acting on a wire 1 meter long with 1 A flowing in a uniform magnetic field is 1 N (Newton), this field has the magnetic flux density of 1 T.
A field of one Tesla is quite strong: the strongest fields available in laboratories are about 20 Teslas, and the Earth's magnetic flux density, at its surface, is about 50 microteslas (μT).
An alternate unit of magnetic flux is gauss (G), where 1 G=10-4 T (0.0001 T), 1 T=104 G.
The relation between B and H is given as follows:B=μHWhere μ is the environment permeability. The relation μ=μr. μo is used, where μr is relative permeability and μo is the permeability of a vacuum. In biological systems permeability is close to that of air and therefore B≈H.
There are three established physical mechanisms through which static and time-varying magnetic fields interact with living matter.
Magnetic Induction: relevant to both static and time varying magnetic fields, originates through the following interactions:                1. Electrodynamic interactions with moving electrolytes are based on Lorenz forces on moving ionic charge carriers and thus electric fields and currents are induced. This type of interaction is the basis of magnetically induced blood flow potentials that have been studied with both static and time varying magnetic fields.        2. Faraday currents—relevant to time varying magnetic fields only. Most scientists consider this interaction as the key mechanism of magnetic therapy with time varying magnetic fields.        3. Magnetomechanical Effects: relevant mainly to static magnetic fields: In uniform magnetic fields, both diamagnetic and paramagnetic molecules experience torque, which tends to orient them in a configuration that minimizes their free energy within the field. When the fields used for magnetic therapy are relatively weak (10 to 100 mT), a magnetomechanical action may not be significant. Magnetomechanical translation can be found in high gradient static magnetic fields that leads to the motion of either paramagnetic or ferromagnetic particles. This action may not be a significant contributor of magnetic therapy effects.        4. Electronic Interactions: seen with static fields but may also be relevant to time varied fields: Some chemical reactions are based on an action on radicals. In these circumstances static magnetic fields exhibit an effect on electronic spin states. It is possible that, although the lifetimes of the intermediates caused by this interaction are short, they can still be a sufficiently strong influence on biological matter via changed kinetics of dynamic chemical reactions.Faraday's Law and Current Density        
Generally, time varying magnetic fields, versus static fields, have been useful for therapeutic purposes since it is most commonly believed that if the key mechanism of action is induction of electrical currents, the appropriate approach is the use of time varying magnetic fields. In accord with Faraday's law, magnetic fields that vary in time will induce potentials and circulating currents in biological systems, including the human body. Current density can be estimated using following formula:J=E.σ=nr2/2nr.dB/dt. σ=σr/2.dB/dtFor sinusoidal fields a simplified equation is appropriate:J=n.r.f.σ.BWhere J=current density (A/M2)
E=induced potential (V/M)
r=radius of the inductive loop (M)
σ=tissue conductivity (S/M)
dB/dt=rate of change of magnetic flux density
It has been determined that current density up to 100 mA/M2 is safe. From this viewpoint, to assure maximum safety we consider the highest conductivity of tissue, i.e. 0.2 S/m. However, this calculation is more theoretical than practical since the human body constitutes many tissues with differing conductivity values. This is the primary reason why we cannot calculate exactly the level of induced currents in the complicated, non-homogenous structures of the body.
Prior art MRT devices provide analog drive signals and analog electromagnetic fields, which are inefficient and result in excessive generation of heat. An object of the present invention is to provide efficient apparatus for the generation of electromagnetic waves utilizing digital electronics and providing magnetic waveforms with a variety of waveform patterns, and a thermal limiter or shutoff circuit when temperatures exceed a predetermined threshold.